/***** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * License Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2010 Ola Bini <ola.bini@gmail.com>
 * 
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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package org.jruby.util.io;

import java.io.IOException;
import java.nio.channels.Selector;
import java.nio.channels.spi.SelectorProvider;

import java.net.BindException;

import org.jruby.Ruby;

/**
 * @author <a href="mailto:ola.bini@gmail.com">Ola Bini</a>
 */
public class SelectorFactory {
    // If it doesn't work after 20 times it's unlikely to ever work. Bailout is only option.
    private final static int RETRY_MAX = 20; 
    
    public static Selector openWithRetryFrom(Ruby runtime, SelectorProvider provider) throws IOException {
        int retryCount = 0;
        while(true) {
            try {
                return provider.openSelector();
            } catch(IOException e) {
                if(e.getMessage() != null && 
                   e.getMessage().contains("Unable to establish loopback connection") && 
                   e.getCause() instanceof BindException &&
                   retryCount < RETRY_MAX) {
                    retryCount++;
                    if(runtime != null) {
                        runtime.getWarnings().warn("try number " + retryCount + " to get a selector");
                    }
                } else {
                    throw e;
                }
            }
        }
    }
}// SelectorFactory
